Centrifuge Investigation of Seepage-Induced Surface Settlement and Particle Loss Near Tunnel Openings

Abstract Leakage of tunnel can induce particle loss, leading to significant safety risks on ground collapse and continuous damage to tunnel structures. Although previous studies have addressed seepage-induced deformation, experimental methods have faced challenges in reproducing realistic stress conditions and capturing localized interactions. This study proposes a centrifuge modeling approach and its detailed testing procedure, to investigate seepage-induced particle migration and associated ground deformation under properly scaled stress conditions. Layered ground conditions from three representative tunnel sites were modeled, incorporating site-specific geotechnical and hydraulic properties. Test results revealed that seepage erosion significantly increased surface settlement above tunnel openings. Comparative analysis across the test cases and with numerical simulations confirmed that the proposed centrifuge modeling effectively captured complex soil-fluid interactions, including transient seepage, particle migration, and localized erosion near the tunnel opening, consistent with prior observations. Notably, the simultaneous monitoring of flow rate, surface settlement, and pore pressure enabled the quantitative identification of repeated formation and collapse of soil arches driven by soil–water leakage. These findings demonstrate that centrifuge modeling offers a practical and scalable experimental framework for evaluating seepage-induced deformation and provides valuable insights for assessing and mitigating tunnel leakage risks in layered ground conditions.